Commitments and Contingencies (Details) (USD $)	1 Months Ended		0 Months Ended	1 Months Ended	0 Months Ended	1 Months Ended	3 Months Ended	5 Months Ended	9 Months Ended
	Sep. 30, 2011	Feb. 28, 2011 insurer	Feb. 17, 2011	Oct. 13, 2010 County	May 18, 2010	May 31, 2007 company	Mar. 31, 2011	Jun. 06, 2008 Well Drycleaner	Sep. 30, 2011 complaint arbitration party	Sep. 30, 2010
Commitments And Contingencies (Textuals)
Number of wells at issue								244
Number of wells at issue as a result of the discovery to date								14
Number of dry cleaners identified by plaintiffs								63
Number of cases in mass tort action				over 100
Number of countries that cases were filed in the mass tort action				17
Complaints in Florida Antitrust Litigation									2
Claims against damages, IDOT/Joliet Road lawsuit					$ 40,000,000
Payment to Illinois Department of Transportation (IDOT)			20,000,000		20,000,000
Number of arbitrations									2
Self-insured retention amount			2,000,000
Number of insurers		3
Number of insurers arbitration completed		2
Settlement awarded	$ 24,111,000	$ 25,546,000					$ 7,500,000			$ 7,600,000
Number of other parties sued in the Lower Passaic River Clean-Up									300
Number of other companies to perform a Remedial Investigation/Feasibility Study related to the Lower Passaic River Clean-Up lawsuit						70